skipping incompatible C libraries?

rgmayoral · 10-16-2007, 01:34 PM

we have installed icc 10.0.025 in an x86_64 machine under CentOS 4.4. Although so far we have succeeded in compiling and running several code samples, we are concerned about warning messages we get while linking, such as:

ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libm.a when searching for -lm
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libdl.so when searching for -ldl
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libdl.a when searching for -ldl
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libnsl.so when searching for -lnsl
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libnsl.a when searching for -lnsl
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libutil.so when searching for -lutil
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libutil.a when searching for -lutil
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libm.a when searching for -lm
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libpthread.so when searching for -lpthread
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libpthread.a when searching for -lpthread
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libc.so when searching for -lc
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libc.a when searching for -lc
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libdl.so when searching for -ldl
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libdl.a when searching for -ldl
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libc.so when searching for -lc
ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../..//libc.a when searching for -lc

does someone know if this is a potential problem that could result in errors in the executables in the future?

weibullguy · 10-16-2007, 02:33 PM

You are on an x86_64 platform, I presume CentOS is compliant and is multilib. Not being familiar CentOS, I can't be 100%. The linker is finding the 32-bit version of the particular library, but wants the 64-bit version. Since the examples build and execute, the linker is ultimately finding the 64-bit version. If it couldn't find the 64-bit library, the build would fail.

On a compliant x86_64 system the 32-bit libraries will live in */lib and the 64-bit in */lib64. You can define a set of env var for 32- and 64-bit in one of your configuration files. Then you can pass these appropriately when you build for the respective ABI. For example:

Code:

export PKG_CONFIG_PATH32="/usr/lib/pkgconfig"
export PKG_CONFIG_PATH64="/usr/lib64/pkgconfig"

export XORG_PREFIX=/usr

export PATH="${PATH}:${XORG_PREFIX}/bin"
export PKG_CONFIG_PATH32="${PKG_CONFIG_PATH32}${PKG_CONFIG_PATH32+:}${XORG_PREFIX}/lib/pkgconfig"
export PKG_CONFIG_PATH64="${PKG_CONFIG_PATH64}${PKG_CONFIG_PATH64+:}${XORG_PREFIX}/lib64/pkgconfig"

export BUILD32="-m32 -pipe -O2 -mtune=athlon64"
export BUILD64="-m64 -pipe -O2 -mtune=athlon64"
export LD_BUILD32="-m elf_i386"
export LD_BUILD64="-m elf_x86_64"

Then you could configure for 64-bit thusly

Code:

CC="gcc ${BUILD64}" PKG_CONFIG_PATH="${PKG_CONFIG_PATH64}" \ 
./configure --prefix=/usr --libdir=/usr/lib64

rgmayoral · 10-18-2007, 06:29 AM

Thank you so much for replying. In the end we found that the easiest solution was to add -L/usr/lib64 in our ifort compiler wrapper (/opt/intel/fce/10.0.023/bin/ifort), so now we have

Code:

if [ $# != 0 ]
then
 exec -a "/opt/intel/fce/10.0.023/bin/ifort" /opt/intel/fce/10.0.023/bin/ifortbin -L/lib64 -L/usr/lib64 "$@";
else
 exec -a "/opt/intel/fce/10.0.023/bin/ifort" /opt/intel/fce/10.0.023/bin/ifortbin;
fi